technique to manipulate water waves to precisely control floating objects

Where there's water, there are waves. But what if you could bend water waves to your will to move floating objects? Scientists have now developed a technique to merge waves in a water tank to produce complex patterns, such as twisting loops and swirling vortices. Some patterns acted like tweezers or a 'tractor beam' to hold a floating ball in place. Other patterns made the ball spin and move precisely in a circular path. In the future, the technique could be scaled down to precisely move particles the size of cells for experiments, or scaled up to guide boats along a desired path on the water.